This Small Business Innovation Research Phase I proposal addresses the problem of hematopoietic stem cell purification and analysis. current methods for stem cell isolation stimulate proliferative CD34+bone marrow cells with the cytokines Kit Ligand (KL) and interleukin-3 (IL-3) in the presence of 5-fluorouracil, a cytotoxic agent. Repliating cells are killled by this treatment leaving an essentially pure population of stem cells. However, it is likely that 5-fluorouracil has some cytotoxic or mutagenic effect on stem cell populations posing distinct problem if steam cells are to be used for therapy. We propose to encapsulate CD34+ bone marrow cells in agarose micro drops, stimulate proliferative cells with KL and IL-3, and purify quiescent cells by florescent staining and cell sorting. Isolated cells will be analyzed using a long term culture initiating cell assay for their ability to give rise to cells of mixed myeloid lineages. Research on pluripotent stem cells have taken on new urgency with recent advances in cell engineering. Development of new methods to select and culture steam cells is expected to advance the technology for therapeutic and commercial research use.